Dyeing of Organic Cotton Fabric using Conventional and ...

Dyeing of Organic Cotton Fabric using Conventional andUltrasonic Exhaust Dyeing Method

UZMA SYED*, ABDUL SAMAD** AND FAREED AHMED**

RECEIVED ON 26.12.2012 ACCEPTED ON 20.03.2013

ABSTRACT

In this research dyeing behavior of organic cotton woven fabric using ultrasonic technique and

conventional dyeing method has been compared. The fabric samples were dyed with reactive dyes

Drimarene Red Cl-5B and Drimarene Blue Cl-BR (0.5% owf) using exhaust dyeing method. The samples

were ultrasonically dyed at varied temperature (60, 50 and 40oC) for 60, 50, 40 and 30 minutes and for

conventional method at varied temperature but at recommended time, 60 minutes. For optimizing the

dyeing behavior, the samples were causticized by pad-batch method and then dyed with ultrasonic technique

at varied temperature and time. It has been observed organic cotton fabric dyed using ultrasonic exhaust

method at 60oC for 50 minutes gives highest (K/S)λλλλλmax value, excellent fastness property, deeper dye

diffusion and less surface deterioration compared to the conventional dyeing method. Moreover,

causticized and dyed sample with ultrasonic technique at 60oC for 30 minutes gives colour strength

value almost equal to the conventional recommended dyeing method. Hence, dyeing of organic material

using ultrasonic exhaust method saves energy and time.

Key Words: Ultrasonic, Exhaust Dyeing, Organic Cotton Fabric, Temperature, Time.

* Assistant Professor, and ** Post-Graduate Student,Department of Textile Engineering, Mehran University of Engineering & Technology, Jamshoro.

1. INTRODUCTION

dyeing, microwaves etc each of these techniques areapplied by different method [2-4]. However, dyeing processeffected on the physical and mechanical properties of thecotton fabric [5-6].

Among all, ultrasonic dyeing is a novel technique to save

time, cost, energy and provides high value of dye uptake.

Ultrasonic waves are high frequency (20-40 KHz) and high

energy waves then the sound waves and can be used for

a variety of purposes. It speeds up the rate of collision of

Mehran University Research Journal of Engineering & Technology, Volume 32, No. 2, April, 2013 [ISSN 0254-7821]329

Organic cotton fibers are produced from non-genetically modified plants and are grownwithout synthetic agricultural chemicals [1].

The fibers offer surface protection of groundwater qualityand reduce environmental damages. In addition,nowadays along with textile fibers, textile processingsector is focusing on the conservation of energy. Thiscan be achieved by processing the textile materials usingvarious techniques such as infrared heating, ultrasonicdyeing, plasma technique, radiofrequency, electrochemical

Dyeing of Organic Cotton Fabric using Conventional and Ultrasonic Exhaust Dyeing Method


molecules, hence resulting in generation of heat and

energy. The use of ultrasonic energy in dyeing optimizes

the dyeing process. Moreover, it can be used for dyeing

both hydrophilic and hydrophobic fibers. Brauer reported

that the ultrasonic dyeing technique saved the dyeing

time of cellulosic fabric with vat dyes. Compared to the

conventional desizing technique; [7] ultrasonic desizing

reduced the fibre degradation while the degree of

whiteness and wet ability of the cellulosic fabric remained

same. Ultrasonic scouring of wool fibres reduced the fiber

damage. Similarly, in bleaching of cotton fiber with

hydrogen peroxide using ultrasound technique at the

frequency of 20 KHz, increased the bleaching rate and

enhanced the degree of whiteness. The mercerization of

cotton material using ultrasonic technique swelled 35%

fiber diameter [8].

The use of ultrasonic energy in dyeing of cotton fabric

samples with monochlorotriazine and vinylsulphone

reactive dyes could result in energy saving, less water

consumption, increased colour depth and reduced

processing time. Linen fabric sample dyed using ultrasonic

technique at 50oC were given slightly higher colour

strength values than those obtained using conventional

dyeing method at 80oC [9].

The colour strength values obtained for the nylon-6

samples dyed using ultrasonic power were higher than

those obtained using conventional method. In addition,

the effect of alkaline soaping treatment on dye fixation for

the dyed fabric samples with different class of reactive

dyes, at both acidic and neutral pH, gave good to excellent

fastness properties with ultrasonic probe technique than

with conventional heating. The utilization of ultrasonic

wave for cold pad-batch dyeing decreased the batching

time at minimum quantity of alkali concentration [10-11].

Knitted interlock fabric dyed at 600 KHz ultrasonic

frequencies, temperature (30-50oC) and salt concentrations

(60g dm-3) showed deeper hue in comparison with that

achieved by conventional method [12].

Hence, radcure techniques using ultrasonic, minimize the

processing time, temperature and energy. Much work has

been carried out on pre-treatment and dyeing of cotton

and other synthetic material but no work was done on the

comparison of dyeing behaviour of organic cotton material

using conventional and exhaust deying ultrasonic

technique. Therefore, in this research organic cotton

material is dyed with reactive dyes; Drimarene Red Cl-5B

and Drimarene Blue Cl-BR (0.5% owf) using conventional

and ultrasonic technique at varied temperature and time.

For optimizing the dyeing bahviour the fabric samples

were causticized and dyed with ultrasonic technique. The

dyeing behaviour was then assessed with colour strength

values, washing fastness, dye uniformity and surface effect

using scanning electron microscopy.

2. MATERIALS

100% bleached organic cotton fabric as mentioned in

Table 1 was purchased from Yunus Textile Mills,

Pakistan. Reactive dyes, Drimarene Red Cl-5B and

Drimarene Blue Cl-BR and other auxiliaries such as

detergent, Ladipur RSK and leveling agent, Drimagen

E2R were kindly supplied from Clariant, Karachi,

Pakistan. Common salt, NaCl and acetic acid were

marketed by Merck, Germany.

TABLE 1 FABRIC SPECIFICATION

Weave Plain

Ends Per Inch 30

Picks Per Inch 30

Warp Count, tex 76

Weft Count, tex 68

Gram Per Square Meter 150



3. METHODS

3.1 Conventional Dyeing

Organic cotton fabric sample of weight 3gm was takenand dyed (0.5% owf) on Rapid HT dyeing machine usingconventional dyeing method as shown in Fig. 1 [13]. Thedyeing process was carried out at liquor to goods ratio of20:1 at 60°C with dye, Drimagen E2R solution w/v (2 gl-1)and salt solution w/v (60 gl-1). After exhaustion (30 minutes)alkali solution w/v (15 g l-1) was added and then processedfor further 45 minutes at the same temperature. Afterdyeing, fabric sample was washed with cold water for 10min then warm water at 80ºC for 10 minutes. The soapingwas done at 90°C for 30 minutes and before dried in anoven it was again warm and cold wash for 10 minuteseach. For comparison the conventional dyeing to theultrasonic dyeing method, it was proceeding at variedtemperature such as 60, 50 and 40oC but at recommendedtime 60 minutes (C60) for exhaustion and fixation phases.

3.2 Ultrasonic Dyeing

Organic cotton sample of weight 3gm was taken and dyed(0.5% owf) on Ultrasonic Cleaner KB200 Series using samerecipe and procedure as mention in conventional dyeing

method (Fig. 1). In addition, the fabric samples were dyedat varied temperatures such as 60, 50 and 40oC and at eachtemperature 60 minutes (U60), 50 minutes (U50), 40 minutes(U40) and 30 minutes (U30) for exhaustion and fixationphases. However, washing was carried out usingrecommended method [13].

3.3 Causticisation

For optimizing the organic cotton fabric dyeing behavior,

the fabric samples were pre-treated using caustic, sodium

hydroxide (2 mol dm-3) by pad-batch method for 30 minutes

[14]. The fabric samples were then dyed by ultrasonic

technique at varied temperature and time as discussed in

preceding Section.

3.4 Colour Strength

The spectral reflectance values (400-700nm) were measured

using a Data Colour Spectrophotometer. For each sample,

readings were taken four times, each at different position.

The percentage reflectance values 'R' were converted to

K/S values, using the formula shown in Equation (1).

( )R

RSK

200

2100/

−= (1)

3.5 Washing Fastness

Fastness to washing test was performed according to the

standard of BS EN ISO 105-CO3: 1998 or BS EN 20105-

CO3:1993. After washing, fabric sample and multi fibres

stripe were then rated (1-5) using grey scale and staining

scale. Where 1 means poor fastness and 5 means excellent

fastness.

3.6 Dye Uniformity

Uniformity of dyeing was assessed using Motic video

microscope. For preparing the yarn cross-sectional images;

7-10 yarns were taken from the dyed fabric and were laidFIG. 1. DYEING PROCEDURE



parallel [14]. The yarn was then passed from the slide; the

extra yarns were then cut using sharp blade. The slide was

then placed on a video microscope and at constant

magnification yarns cross-sectional images were then

captured.

3.7 Surface Effects

For assessing the surface distortion of dyed fabric sample

with conventional and ultrasonic dyeing method, fabric

samples of 1x1cm was taken. The fabric images at 700

magnifications were captured using JEOL JSM 5380 LV.

The fabric images were then visually analyzed.

4. RESULTS AND DISCUSSION

4.1 Effect of (K/S)λλλλλmax Value at 60, 50 and40oC Dyeing Temperatures

It has been observed from Figs. 2-3 that the ultrasonic

dyed samples with Drimarene Blue Cl-BR and Drimarene

Red Cl-5B (0.5% owf) at 60oC dyeing temperature for 50

minutes gives the highest (K/S)λmax values than the

conventional dyed samples. However, dyeing time for

40 and 30 minutes, the (K/S)λmax values are decreasing

at all dyeing temperature 60, 50 and 40oC. The colour

strength value for 50 minutes dyeing time is higher than

the 60 minutes dyeing time at all dyeing temperature

(60, 50 and 40oC). It is because for 60 minutes dyeing

cycle fibre fibrils are propensities on the fabric surface.

Hence, hinder the reflectance of light and gives less

colour strength value.

When comparing the colour strength values among 60,

50 and 40oC dyeing temperature, dyeing at recommended

temperature (60oC) gives highest colour strength value

than the 50 and 40oC both by ultrasonic and

conventional dyeing methods. Moreover, the colour

strength value dyed with Drimarene Red Cl-5B is higher

than the Drimarene Blue Cl-BR at 60oC dyeing

temperature for 50 minutes. It is due to the difference in

dye molecular size of Drimarene Red Cl-5B and

Drimarene Blue Cl-BR dye. The small molecular size of

dye molecules make easy for dye molecules to penetrate

into the amorphous regain of polymer of fibre filaments

at low temperature and less time.

The percent (K/S)λmax value relative to conventional dyeing

method for 60 minutes (C60) to ultrasonic dyed samples at

various temperature and time are shown in Figs. 4-5. It has

been observed that the (K/S)λmax value of conventional

dyed samples is lower to all ultrasonic dyeing method

except dyeing for 40 and 30 minutes at 60 and 50oC for

exhaustion and fixation phases. Ultrasonic dyeing at 40oC

gives the lowest (K/S)λmax value on the contrary, it shows

much higher (K/S)λmax values relative to C60. It is because

FIG. 2. (K/S)610NM VALUES OF DRIMARENE BLUE CL-BRDYED SAMPLES

FIG. 3. (K/S)550NM VALUES OF DRIMARENE RED CL-5B DYEDSAMPLES



radcure technique using ultrasonic waves provides much

higher energy to dye molecules thus increases the rate of

diffusion and exhaustion as compared to conventional

dyeing method.

The ultrasonic dyeing of organic cotton woven fabricshows less than to 120% improvement when dyeing at 60and 50oC for both 60 and 50 minutes dyeing cycle comparedto conventional dyeing.

4.2 (K/S)λλλλλmax Values of Causticized DyedSamples

Figs. 6-7 shows that pre-treatment using sodium hydroxideimproves the (K/S)λmax value. The trend of (K/S)λmax valueis almost same for the Drimarene Red Cl-5B and DrimareneBlue Cl-BR (0.5% owf). It is observed that the (K/S)λmax

value of pre-treated and ultrasonic dyed sample is almostdouble to the conventional dyed sample. It is because thecaustic soda swells up cellulosic fibers, hence allow thedye molecules to penetrate in to the fibre filaments.Similarly, ultrasonic cavitation assists the dye moleculesto exhaust towards the fibre filaments. Thence, improvesthe (K/S)λmax values, decreasing nearly 40-50% dyeingcycle.

The dyeing at 60oC for 60 minutes using ultrasonictechnique (U60) gives highest (K/S)λmax values in bothDrimarene Red Cl-5B and Drimarene Blue Cl-BR (0.5% owf).The ultrasonic dyeing with caustic pre-treatment atrecommended temperature and half dyeing time (30minutes) gives colour strength value as with C60. Hence,organic cotton fabric can be dyed at reduce dyeing time at60oC dyeing temperature. On the contrary causticizationprocess is required an additional cost.

FIG. 4. (K/S)610NM RELATIVE TO C60 IN %, DYED WITHDRIMARENE BLUE CL-BR 0.5% OWF

FIG. 5. (K/S)550NM RELATIVE TO C60 IN %, DYED WITHDRIMARENE RED CL-5B 0.5% OWF

FIG. 6. (K/S)610NM VALUES OF CAUSTICIZED AND THENDRIMARENE BLUE CL-BR DYED SAMPLES

FIG. 7. (K/S)550NM VALUES OF CAUSTICIZED ANDDRIMARENE RED CL-5B DYED SAMPLES



Similar to Figs. 4-5, Figs. 8-9 shows the same trend of

colour strength value. The pre-treated and then dyed

sample by ultrasonic technique gives 130-240% high colour

strength value than the sample dyed by conventional

dyeing technique (C60) at all dyeing temperature and time

for exhaustion and fixation phase.

4.3 Washing Fastness

Organic cotton fabric when dyed with reactive dyes

shows inconsiderable change in shade and staining

rating. Hence, fastness to washing is more depended on

the dye type rather than dyeing methods. Reactive dye

molecules formed a strong covalent bond with cellulosic

fabric and gives very good to excellent washing fastness

properties. It is observed Drimarene Red Cl-5B gives the

highest (K/S)λmax values and shows no staining and

colour change when dyed by conventional and

ultrasonic dyeing method at 60oC dyeing temperature.

While fabric dyed with Drimarene Blue Cl-BR shows

slight change in shade when dyed by conventional

dyeing method (C60 at 60oC) and ultrasonic dyed at 60oC

dyeing temperature for 30 minutes.

The staining rating (4-5) on cotton fabric is observed

when Drimarene Blue Cl-BR and Drimarene Red Cl-5B is

dyed at 50 and 40oC for 40 and 30 minutes dyeing cycle

by ultrasonic technique. Pre-treatment using sodium

hydroxide improves the washing fastness rating at 60oC

dyeing temperature and 40 and 30 min dyeing time with

both Drimarene Blue Cl-BR and Drimarene Red Cl-5B

dye. However, staining rating (4-5) on cotton fabric has

been observed when dyeing was performed at 50oC for

40 and 30 minutes using both dyes by ultrasonic dyeing

method.

4.4 Dye Uniformity

The uniformity of dye molecules in to the fibres

filament of the yarns of the fabric was assessed using

optical microscope. The images after capturing were

assessed manually. It has been observed that the

fabric sample dyed by conventional dyeing methods

shows less diffusion of dye moleclues both with

Drimarene Blue Cl-BR and Drimarene Red Cl-5B as

compared to ultrasonic dyeing technique as shown

in Figs. 10-11.

In case of ultrasonic dyeing method, sample dyed at 60oC

for 60 and 50 minutes shows much deeper diffusion of dye

FIG. 8. (K/S)610NM RELATIVE TO C60 IN %, CAUSTICIZEDAND DYED WITH DRIMARENE BLUE CL-BR 0.5% OWF

FIG. 9. (K/S)550NM RELATIVE TO C60 IN %, CAUSTICIZED ANDDYED WITH DRIMARENE RED CL-5B 0.5% OWF



molecules, hence, high dye uptake values and dye

uniformity. The fabric samples dyed after causticisation

also shows uniform dyeing and deeper diffusion of dye

molecules as shown in Fig. 12.

FIG. 10(a) DYED SAMPLE WITH DRIMARENE BLUE CL-BR BY CONVENTIONAL DYEING METHOD AT 60oC FOR 60 MINUTES (b)DYED WITH DRIMARENE BLUE CL-BR BY ULTRASONIC TECHNIQUE AT 60oC FOR 60 MINUTES (c) DYED WITH DRIMARENE BLUE

CL-BR BY ULTRASONIC TECHNIQUE AT 60oC FOR 50 MINUTES

FIG. 11(a). DYED WITH DRIMARENE RED CL-5B BY CONVENTIONAL DYEING METHOD AT 60oC FOR 60 MINUTES (b) DYED WITHDRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 60 MINUTES (c) DYED WITH DRIMARENE RED CL-5B BY

ULTRASONIC TECHNIQUE AT 60oC FOR 50 MINUTES

FIG. 12(a)CAUSTICISED AND DYED WITH DRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60ºC FOR 60 MINUTES, (b)CAUSTICISED AND DYED WITH DRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 50 MINUTES (c)CAUSTICISED AND DYED WITH DRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 40 MINUTES (d)

CAUSTICISED AND DYED WITH DRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 30 MINUTES



4.5 Surface Effect

The SEM images of fabric sample dyed by conventional

dyeing technique are shown in Fig. 13(a) gives lower (K/S)λmax values and surface deterioration as compared to

the sample dyed by ultrasonic technique as shown in

Fig. 13(b). The sample dyed by ultrasonic technique at60oC for 60 minutes shows that surface of sample is

deteriorated by ultrasonic waves, making its fibrils

protruding, hence gives lower (K/S)λmax value ascompared to sample dyed for 50 minutes. Less

deterioration of fabric surface gives regular refection of

light hence high (K/S)λmax values.

Pre-treated and dyed sample has an insignificant surface

deterioration due to the combined action of causticization

and ultrasonic waves during fabric processing. Few fibre

fibrils are protruding on the fabric surface thus gives quite

high colour strength values as shown in Fig. 14.

5. CONCLUSION

Radcure using ultrasonic technique is an environmental

friendly and sustainable dyeing method saves dyeing

assistant, time and temperature. In this research

bleached organic cotton fabric samples were dyed with

ultrasonic and conventional dyeing method at varied

FIG. 14(a). CAUSTICISED AND DYED WITH DRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 60 MINUTES (b).CAUSTICISED AND DYED WITH DRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 50 MINUTES

FIG. 13(a). DYED WITH DRIMARENE RED CL-5B BY CONVENTIONAL DYEING METHOD AT 60oC FOR 60 MINUTES (b) DYED WITHDRIMARENE RED CL-5B BY ULTRASONIC TECHNIQUE AT 60oC FOR 60 MINUTES (c) DYED WITH DRIMARENE RED CL-5B BY

ULTRASONIC TECHNIQUE AT 60oC FOR 50 MINUTES



temperature and time. It is observed that the ultrasound

waves improves 25% colour strength values with

Drimarene Red Cl-5B (0.5% owf) and 8% colour strength

values with Drimarene Blue Cl-BR (0.5% owf). Among

temperature and time variations, sample dyed using

ultrasonic technique at 60oC for 50 minutes gives

highest (K/S)λmax values both Drimarene Red Cl-5B and

Drimarene Blue CL-BR dyes. It is because for 50 minutes

dyeing cycle, less deterioration on fabric surface and

deeper diffusion of dye molecules is observed as

compared to dyeing for 60 minutes dyeing cycle at 60oC

dyeing temperature. However, combine action of caustic

and ultrasonic waves swell up the fibre filaments cause

much deeper diffusion of dye molecules and highest

colour strength value of organic cotton fabric.

Furthermore, insignificant change in fabric surface is

observed. The causticization and dyeing with ultrasonic

technique almost half the dyeing time compared to

conventional dyeing methods, hence save energy and

cost.

ACKNOWLEDGEMENTS

The authors acknowledge the cooperation of technical

staff of Department of Textile Engineering, Mehran

University of Engineering & Technology, Jamshoro,

Pakistan, for conducting research and Prof. Dr. Abdul

Ghani Pathan, Department of Mining Engineering, Mehran

University of Engineering & Technology, Jamshoro,

Pakistan, for conducting the SEM images.

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